DESCRIPTION: (Verbatim from the Applicant's Abstract) Aluminum has long been suspected to play a role in several neurological diseases associated with aging, but this linkage has never been unequivocally established. The relative inertness of aluminum salts has been cited as negating this possibility. Paradoxically, the investigator's recent findings suggest that this very inertness may provoke a neurotoxic response. In addition, although aluminum has no intrinsic pro-oxidant properties, they have evidence that the potential of transition metals for enhancing free radical generation in nervous tissue is enhanced by aluminum. These findings serve as the foundation for the following research objectives: (1) To define the precise chemical and molecular basis underlying aluminum's potentiation of transition-metal induced free radical activity within nervous tissue. The effect of aluminum on Fenton chemistry and oxidation state of several transition metals will be examined. (2) To locate the anatomical regions and cell types in which aluminum can effect tissue damage. (3) To define the sequence of the intracellular signaling cascades in doses animals and in human (neuronal and glial) cell lines responding to aluminum exposure. Second messenger pathways and consequent changes in transcription factors will be documented. Key proteins such as ubiquitin, cytokines, HSP 70, zinc finger proteins and NFkB will be quantified by immunological or gel shift procedures. Whether the properties of aluminum colloid can be intrinsically toxic or whether the toxicity of beta-amyloid can be enhanced will be determined. (4) To tract the effects of extended aluminum exposure upon genomic expression within neural tissues. This will include assay for deletions in mitochondrial DNA. (5) To explore possible pharmacological interventions that may prevent changes within neural tissues exposed to aluminum. This will involve dietary or growth media supplementation with antioxidant agents or the use of selective chelators. Together, these five objectives delineate a research strategy that will allow resolution of the seemingly contradictory evidence relating aluminum to neurological degeneration.